Suitable For: This 5 button exerciser is specially designed for many musical instruments, like guitar, trumpet. It also helps your finger strength. Adjustable Tension: Individual finger tension is adjustable, ranging from 3LB to 8.5LB. You can lock 2 buttom simultaneously, so you can select different tension for each finger and choose which fingers you want to exercise as you like. Durable: Environmental silicone provides good grip during exercise. exercise and the copper spring provides good resilience for strength building. Comfortable: anti-slip granule on the silicone surface, it is not easy to slip off your palm ; Groove design of the buttom makes a comfortable press. Portable: With portable size, you can carry it in your luggage, pocket, purse, purse, etc., force your fingers to any time whenever you want.